There is an urgent need for detection technologies that enable accurate and precise quantification of solutions containing small organic molecules in a manner that is rapid, cheap, non-labor-intensive, readily automated, and without a requirement for specific analyte standards. We provide a theoretical analysis that predicts that the logarithmic nature of the working domain of the evaporative light-scattering detector (ELSD) will normally bias toward underestimation of chromatographically resolved impurities, resulting in an overestimation of analyte purity. This analysis is confirmed by experiments with flow injection analysis (FIA) and gradient reversed-phase high performance liquid chromatography (RP-HPLC). Quantification is further compromised by the dependence of response parameters on the matrix composition and hence on the retention time of the analyte. Attempts were made to ameliorate these problems by using the response surface of a single compound to calibrate throughout the HPLC gradient. A chemiluminescent nitrogen detector (CLND) was also used in a similar manner, and the performance of the two techniques were compared against those of each other and that of a reference standard technique. A protocol for this purpose was developed using proton nuclear magnetic resonance (1H NMR) and the ERETIC method to enable quantification by integrating proton signals. The double-blind comparison exercise confirmed molar nitrogen CLND response to be sufficiently stable and robust across a methanol gradient to be used with a single external nitrogenous calibrant to quantify nitrogen-containing compounds of known molecular formula. The performance of HPLC-CLND was very similar to that of NMR, while that of HPLC-ELSD was seen to be significantly worse, showing it to be unsuitable for the purpose of single-calibrant quantification. We report details and experience of our use of RP-HPLC-CLND-MS to characterize and quantify small amounts of solutions of novel compounds at nominal levels of 10mM in microtiter plate (MTP) format.

Quality by design (ICH-Topic Q8) requires a prospective summary of the desired quality characteristics of a drug product. This is known as the Quality Target Product Profile (QTPP), which forms the basis for the design and development of the product. An analogous term has been established for analytical procedures called the Analytical Target Profile (ATP). The ATP, in a similar fashion to the QTPP, prospectively summarizes the requirements associated with a measurement on a quality attribute which needs to be met by an analytical procedure. Criteria defined in the ATP relate to the maximum uncertainty associated with the reportable result that is required to maintain acceptable confidence in the quality decision made from the result. The ATP is used to define and assess the fitness of an analytical procedure in the development phase and during all changes across the analytical lifecycle. One or more analytical procedures can meet the requirements of an ATP. The ATP can be applied to any quality attribute across any pharmaceutical modality where an analytical procedure is used to generate a reportable result, and this paper provides examples from three of these modalities: small molecules, oligonucleotides, and vaccines. Some key performance characteristics will be discussed for each ATP, namely specificity, accuracy, and precision, taking into account the expected range of the analyte. The combination of accuracy and precision into a combined uncertainty characteristic is also discussed as a more holistic approach. The use of the ATP concept will help focus attention on the properties of a method which impact quality decisions rather than method descriptions and may enable greater regulatory flexibility across the lifecycle using established conditions based on method performance criteria as proposed in the Step 2 version of ICHQ12. The revision of ICHQ2(R1) and development of the new ICHQ14 guideline (Analytical Procedure Development) will provide a golden opportunity to harmonize the definition of new QbD concepts such as the ATP.A nalytical technology, method development, validation, and technical transfers are encountered across many manufacturing industries, including the pharmaceutical, fine

Method equivalence assessments should be considered when analytical methods are either modified or substituted. The TOST (two one sided tests) approach provides a sounder data driven method for testing equivalence than a simple comparative intermediate precision study which is typically performed as part of method validation. Prior to designing an equivalency study, an acceptance criterion (an acceptable bias between original and modified/changed method) must be chosen. The choice of acceptance criteria requires the identification of the smallest mean difference or bias between methods that is practically important. Equivalence testing in this manner is used to prove that the new method can generate data which continues to support previously established specifications. Once the acceptance criterion is decided, other aspects of the study can be designed following a set of design principles. When the design and acceptance criteria have been established, the collection of the data can commence. Demonstration of equivalence should not start until the validity of the observations has been confirmed such as assessment for outliers, normality, and comparison of variances. Once the suitability of the data is confirmed, the mean difference between the two data sets can be calculated along with a +/-90% confidence interval using the TOST approach. It can then be established whether equivalence of the two methods has been demonstrated.

Pharmaceutical companies have a continuous need to resolve new racemates. Analysis may be required in aqueous and nonaqueous media, or in the presence of several different sets of potentially interfering compounds. There is often a preparative requirement. For these reasons analysts may require a number of different separation systems capable of resolving a given pair of enantiomers. We wished to improve upon existing approaches that address this situation and undertook a program of work to screen over 100 racemates, selected for their chemical diversity, on over 100 different chiral HPLC, SFC, and CE systems. Here we report results of this comparison and illustrate the use of rapid gradient screening as a valuable tool for chiral method development.

A structured approach to method development can help to ensure an analytical procedure is robust across the lifecycle of its use. The analytical target profile (ATP), which describes the required quality of the reportable value to be produced by the analytical procedure, enables the analytical scientist to select the best analytical technology on which to develop their procedure(s). Once the technology has been identified, screening of potentially fit for purpose analytical procedures should take place. Analytical procedures that have been demonstrated to meet the ATP should be evaluated against business drivers (e.g., operational constraints) to determine the most suitable analytical procedure. Three case studies are covered from across small molecules, vaccines, and biotherapeutics. The case studies cover different aspects of the analytical procedure selection process, such as the use of platform method development processes and procedures, the development of multiattribute analytical procedures, and the use of analytical technologies to provide product characterization knowledge in order to define or redefine the ATP. Challenges associated with method selection are discussed such as where existing pharmacopoeial monographs link acceptance criteria to specific types of analytical technology.